Hi My Age Is 25 And I Am Late For

Hi my age is 25 and I am late for my period for almost 2 weeks my last period i got was at 16thjan which ended at 21st Jan I had intercourse on 6th an 7th but with precautions and nothing mishap occured.Usually i got down before 28 dats but for the frst time m late.my doctor prescribed me dub-5 Twice a day for three days. The course got completed on 24th but m not having my periods yet. Now she has prescribed me Amycordial syp twice in a day. I took 3 upt all where negative.. I don't want to get preg and m not getting any clear answer from my doct. Recently i hv detected with subclinical hyperthyroidism. And m getting some abdominal and back cramps and slight white mucus kind of discharge.Can any one Help me